The present invention generally relates to photonic switching systems, and more particularly to a photonic switching system which cross connects, drops or inserts optical signal links of a plurality of channels.
In a broadband integrated services digital network (ISDN), it is necessary to use a transmission apparatus having a throughput in the order of 42.3 Gbps. In other words, it must be possible to cross connect, drop or insert 155.520 Mbps data of approximately 272 channels.
In a conventional system which cross connects, drops or inserts optical signal links of a plurality of channels, the process of cross connecting, dropping or inserting is carried out after once converting a received optical signal into an electrical signal, and the processed electrical signal is converted back into an optical signal before being transmitted to a terminal, a subscriber or a next node.
When carrying out the process electrically, it is necessary to use a large scale integrated circuit (LSI) having a high performance and capable of processing a large number of signals which are transmitted at a high transmission rate, but the performance of the existing LSI cannot meet such a demand. Even if an LSI having such a high performance were existed, the number of input and output pins would become extremely large, it would be extremely troublesome to equip the system with such an LSI, and required coaxial cables and interconnections would become extremely complex and large in scale. For this reason, there is a problem in that it is extremely difficult to realize by the conventional method a switching system which is capable of switching optical signal links as the signal capacity further increases in the future.